September 2014

SCHOTTEL – Focus on hybrid applications and offshore

SCHOTTEL Rudderpropeller SRP 9000 LSU

SCHOTTEL Rudderpropeller SRP 3000 PTI

SCHOTTEL Rudderpropeller SRP 4000 USV

German propulsion specialist SCHOTTEL will be showcasing new propulsion solutions featuring hybrid concepts and offshore applications at SMM 2014. These solutions are primarily geared towards customer demands for more environmentally friendly propulsion systems, not to mention compact, powerful and maintenance-friendly solutions for the open sea.


The successful operation of Svitzer ECOTUGs with the electric SCHOTTEL Combi Drive (SCD) led SCHOTTEL to develop further solutions for vessels with highly variable work cycles. Tugs are required to fulfil a variety of tasks covering the full power spectrum, including periods requiring either very low or very high power (e.g. in standby state or towing operations). Conventional direct diesel driven tugs are rarely operated continuously at the optimal engine power. This results in high fuel consumption and pollutant emissions. SCHOTTEL hybrid concepts allow the tug to be operated as appropriate to its tasks. At part load, the electric motor suffices. The diesel engine is employed for operation at full load, and the electric motor can easily be switched on to provide additional power. In FiFi mode, the electric motor maintains the position and the diesel engine is available to the FiFi pump.


2 x SRP 3000 PTI: 10 knots with an electric motor alone

The latest environmentally friendly tug concepts can be found in the EDDY tug, which has been in service since June, as well as in two tugs currently under construction.

The 65 t BP EDDY TUG is equipped with two SRP 3000 PTIs. This propulsion system consists of a mechanical Rudderpropeller (1900 kW) and a PTI mounted on the above-water gearbox opposite the power input. The PTI is an electric motor which provides 460 kW at 1100 rpm for manoeuvring and transit at up to 10 kn when the diesel engine is switched off. The diesel engine can be used for operation with higher load requirements, and the electric motor can supply supplementary power as needed. This option is available in boost mode, at maximum bollard pull or for high torque requirements at part load.  The system allows for simple switching between diesel and electric operation while on the move, and achieves smooth transitions. The PTI and diesel engine are controlled centrally as a single system.

The SRP 3000 PTI is also available as an SRP 4000 PTI. This concept for high-speed diesel engines can also be applied to ferries.


Strong SCHOTTEL hybrid gearbox

Two 90t BP tugs currently under construction are each to be fitted with two SCHOTTEL SRP 4000s (2240 kW) with SCHOTTEL hybrid gearboxes. The hybrid gearbox is a powerful transmission with a hydraulic clutch and an electric motor (600 kW), enabling the tug to be operated with the diesel engine, the diesel engine and the electric motor or the electric motor alone. This solution is flexible as far as the diesel engine and electric motor are concerned, and it is suitable for hybrid concepts with Rudderpropeller input power ratings of up to 4200 kW.


SCHOTTEL hybrid solutions are particularly customer-friendly – compact and space-saving, simple to install and maintain. These concepts do not require batteries. In addition to reduced fuel consumption and emissions during operation, costs can also be saved at the investment stage. For example, the main propulsion system requires a smaller combustion engine than conventional solutions. In addition, the operating hours of the engine are considerably reduced which leads to a longer service life and less maintenance costs. Furthermore, the electric motor ensures greater reliability as  a redundant device.

Additional hybrid tugs equipped with SCHOTTEL propulsion systems and modern frequency control are currently in service.


Innovative underwater mountable systems

Increasingly high requirements in the offshore sector also challenge suppliers to provide new and innovative solutions. In the search for new oil fields, ever more remote regions of the seas are being explored. However, these areas lack the required infrastructure. With greater and greater distances between the sites of operation and well-equipped ports, it has become necessary today to perform repair, maintenance and exchange tasks directly on site. SCHOTTEL has responded to this requirement with a new underwater mountable system, the SRP 9000 LSU, with a power range of 4800-5500 kW. It is compact and equipped with a hydrodynamically optimized housing. For the different thruster requirements on ships or semi-submersibles, propeller shafts are available as both tilted and standard variants. Bevel gearboxes of robust design ensure long and reliable operation. The SRP 9000 LSU is equipped with a proven sealing system that monitors for leakage and is specially optimized for this range of application. By default, the system is equipped with the SCHOTTEL Condition Monitoring System (S-COM), which collects, records and reports all relevant values concerning the state of the system (such as the temperature of bearings and oil, the vibration level of the various bearings and gearboxes, and particles or water in the oil). This allows impending damage to be detected in advance and appropriate measures to be taken. The developers attached particular importance to the simple and fast exchange of the system without the need for docking.


Compact retractable system

SCHOTTEL has launched a particular innovation on the market to meet the high demands in the offshore sector: the new SRP 4000 USV retractable system (2000-3000 kW) is characterized by a highly compact design, thus enabling low installation heights and avoiding the need to encroach upon the decks above. With the drive motor located beneath and to the side of the helical gearbox as well as the completely redesigned Spindle Drive, this Rudderpropeller variant stands out considerably from the retractable systems available on the market and has a relatively small “footprint” as well.


Not least, SCHOTTEL has expanded its range of Twin Propellers (STP) with a particularly high-performance system that is also specially tailored to demanding offshore requirements. The STP 3040 (3500-3800 kW) has a hydrodynamically optimized design. Speeds of up to 21 knots can be reached depending on the operational profile.